This invention relates to pesticides for use in agriculture and horticulture, including the treatment of ornamental and crop plants.
A number of substances have been used in food and drink preservation and for sterilization of utensils in the food and brewing industries. These include, but are not limited to, the following:
substances capable of releasing chlorine when dissolved in water, e.g. calcium hypochlorite or sodium hypochlorite; PA1 substances capable of releasing sulphur dioxide, e.g. sodium metabisulphite (release may be increased by the addition of citric acid to the sodium metabisulphite); PA1 benzoic acid and salts, e.g. sodium benzoate; PA1 acetic acid; PA1 sorbic acid and salts, e.g. sodium sorbate; PA1 formalin/formaldehyde; PA1 organic compounds containing chlorine that is released on contact with water, e.g. sodium and other dichloroisocyanurates and Chempro sterilant for home brewing; PA1 methyl, ethyl and propyl 4-hydroxybenzoates and their sodium salts; PA1 propionic acid and its salts, e.g. sodium propionate; PA1 hexamine; PA1 biphenyl; PA1 ascorbic acid and its salts, e.g. sodium ascorbate; PA1 2-hydroxybiphenyl and its sodium salts (sodium biphenyl-2-yl oxide); PA1 2-(thiazol-4-yl)-benzimidazole; PA1 the nitrate and nitrite of sodium and potassium; PA1 and nisin.
A list of agents permitted for use in the United Kingdom appears in Statutory Instrument 752 of 1979, (The Food and Drugs Composition and Labelling Preservatives in Food Regulations 1979).
None of these has hitherto been used in controlling fungal or bacterial infection in growing plants, whether grown for crop production or for ornamental purposes.
The effect of these materials lasts only for a short time, sometimes as little as ten minutes, under agricultural conditions. However, such materials are readily available and inexpensive. Many of them are permitted food additives. Moreover, they are non-specific fungicides and bactericides, so that the establishment of resistance to them is unlikely.
Used by themselves at rates from 5 grams to 2.5 kg per hectare they can offer a degree of fungal or bacterial control which is commercially useful in relating to their cost.